The present invention relates to a semiconductor switch circuit and, more particularly, to an integrated circuit suitable for a timer of the type which measures time by charing a condenser with a very small current.
As an example of such a timer, an electronic shutter control circuit is presented. The electronic shutter control circuit has evolved so as to provide a semiconductor switch circuit for controlling the opening and closing of a shutter, to set integration starting conditions for adopting an appropriate amount of exposure light, and starting to integrate time.
However, since the electronic shutter control circuit must be driven with a very small current, MOS transistor switches are not suitable for such a circuit because of their inherent leakage current. Bipolar transistors are also not suitable for such a circuit because their saturation voltage remains between the collector and the emitter of each of the transistors upon conductive conditions. Thus, the accurate operation of the switch circuit could not be expected.